1. Field of the Invention
This invention relates generally to a solenoid assembly for driving a plunger by magnetic force and more particularly to a fastener arrangement for a solenoid assembly to maintain the components in a preset condition during a subsequent molding of a plastic casing about the assembly.
2. Description of the Prior Art
A conventional solenoid assembly has a casing made of metal and is comprised of a coil on a bobbin, a magnetic core, a magnetic plunger and a magnetic yoke which are arranged in the casing. In such a solenoid assembly, the metal casing is sometimes replaced or covered by a casing formed by plastic molding so as to improve the air-tightness of the interior of the solenoid assembly. For example, in a solenoid assembly disclosed in Japanese Kokai Application No. 58(1982)-11180 published on Jan. 24, 1983, a grommet for supporting a lead wire is arranged on a flanged portion formed on a coil bobbin whereby the lead wire is connected to an electric coil and a casing is subsequently formed by a plastic molding operation after all of the parts are arranged to hold the parts in assembled condition. However, during such a plastic molding operation to provide a casing, the grommet may receive non-symmetrical pressures whereby the grommet is displaced from the bobbin or the grommet is tilted relative to the bobbin with the result that the solenoid assembly is malformed.